Preparation and optimization of oxygenated gasolines

Abstract

A process for controlling the composition of an xBOB so that the xBOB will yield an oxygenate-containing gasoline which precisely meets desired specifications when mixed with the desired amount of oxygenate. The process involves blending a plurality of blendstocks to produce an xBOB, withdrawing a sample of the xBOB, obtaining spectroscopic measurements for the sample, applying mathematical models that were based on correlation of xBOB spectra to associated oxygenate-containing gasoline properties, to predict laboratory analysis results for oxygenate-containing gasoline properties, and using the analysis results to control and optimize the blending process.

That which is claimed is: 
     
       1. A method to control an xBOB output stream, which comprises:
 (a) spectroscopically analyzing an xBOB stream to produce spectrum of said analyzed xBOB product; 
 (b) correcting said spectrum mathematically to produce a corrected spectra; 
 (c) applying a calibration model to said corrected spectra; 
 (d) obtaining predicted laboratory results from said calibration model; 
 (e) transferring said predicted laboratory results to a control system; 
 (f) modifying the ratio of blendstock components of said xBOB stream based on said results to produce an xBOB output stream that when said xBOB stream is combined with a fixed, known quantity of a predetermined oxygenate will produce an oxygenate-containing gasoline product having preset physical properties. 
 
     
     
       2. A method in accordance with  claim 1  wherein said xBOB comprises mixtures of hydrocarbons selected form the group consisting of catalytically cracked naphtha, coker naphtha, reformate, virgin naphtha, isomerate, alkylate, raffinate, natural gasoline, polymer gasoline, pyrolysis gasoline, pentane, butane, xylene, toluene, and mixtures thereof. 
     
     
       3. A method in accordance with  claim 1  wherein spectroscopic methods are selected from the group consisting of nuclear magnetic resonance spectroscopy, Raman spectroscopy, infrared (IR) spectroscopy, and one or more thereof. 
     
     
       4. A method in accordance with  claim 1  wherein said spectroscopic method is near infrared spectroscopy. 
     
     
       5. A method in accordance with  claim 1  wherein said oxygenate is a monohydric aliphatic alcohol having from about one to about 10 carbon atoms per molecule. 
     
     
       6. A method in accordance with  claim 1  wherein said monohydric oxygenate is selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pentanol, 2-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol and mixtures of two or more thereof. 
     
     
       7. A method in accordance with  claim 1  wherein said oxygenate is selected from the group consisting of methanol and ethanol. 
     
     
       8. A method in accordance with  claim 1  wherein said physical properties are selected from the group consisting of research octane, motor octane, T10 distillation, T20 distillation, T50 distillation, T90 distillation, E200, E300, olefin content, paraffins content, aromatics content, and benzene content. 
     
     
       9. A method in accordance with  claim 1  wherein said correlation process is a chemometric method selected from the group consisting of partial least squares (PLS), multiple linear regression (MLR), principle component regression (PCR), multivariate regression analyses, and multivariate statistical analyses. 
     
     
       10. A method in accordance with  claim 1  wherein predicted results are transmitted to a control system, wherein said control system can modify the ratio of blendstock components of the xBOB stream to produce an xBOB stream that when combined with a fixed, known quantity of a pre-determined oxygenate composition will produce an associated oxygenate-containing gasoline. 
     
     
       11. A method to control an xBOB output stream, which comprises:
 (a) spectroscopically analyzing an xBOB stream to produce spectrum of said analyzed xBOB product; 
 (b) correcting said spectrum mathematically to produce a corrected spectra; 
 (c) applying a calibration model to said corrected spectra; 
 (d) obtaining predicted laboratory results from said calibration model; 
 (e) transferring said predicted laboratory results to a control system; and 
 (f) modifying the ratio of blendstock components of said xBOB stream based on said results to produce an xBOB output stream that when said xBOB stream is combined with a fixed, known quantity of a predetermined oxygenate will produce an oxygenate-containing gasoline product having preset physical properties, 
 wherein the xBOB stream is a hydrocarbon blendstock prior to a product terminal.